OS X

Came before Vista. Irritating Fanboys and silly marketing campaigns (albeit now Microsoft have emulated them too- see the pattern here?) cloud its actual benefits, but its largely used for its creative capabilities. And when I say, "capabilities" I mean Logic and Final Cut work only on OS X, Industry-standard programs. A 'true' user of OS X is generally quite irritated and bemused by fanboys and marketing campaigns and couldn't careless what OS you use or how much money he/she paid for it, because it works for them and they are rather pleased no one bothers making Virus' for their OS.